Syndiotactic Poly(N-n-propylacrylamide) Shows Highly Cooperative Phase Transition
Syndiotactic Poly(N-n-propylacrylamide) Shows Highly Cooperative Phase Transition
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DOI：
10.1021/la8034837
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发表时间：
2009-01-06
期刊：
影响因子：
3.9
通讯作者：
Maeda, Yasushi
中科院分区：
文献类型：
--
作者：
Mori, Takeshi;Hirano, Tomohiro;Maeda, Yasushi
合成了不同外消旋二联体含量的间规聚N-正丙基丙烯酰胺（PNNPAM），用高灵敏度差示扫描量热法（DSC）和红外光谱（FT-IR）研究了PNNPAM的相转变行为。相变的协同性随着r二联体含量的增加而增加。与无规PNNPAM相比，间规聚合物中的协同单元数增加了2.5 ~ 4倍，这表明了发生协同相变的单体单元长度。从F-F-IR光谱和量子化学计算的结果，它被确定为高的协同性的间同立构聚合物导致在脱水状态下的有序结构的局部形成。
Syndiotactic poly (N-n-propylacrylamide)s (PNNPAM) with various racemo (r) diad contents were synthesized, and their phase transition behaviors were studied by high-sensitivity differential scanning calorimetry and FT-IR spectroscopy. The cooperativity of the phase transition increased with the increase in the r diad content. Compared with the atactic PNNPAM, the number of cooperative units, which shows the monomeric units length undergoing cooperative phase transition, increased 2.5- to 4-fold in the syndiotactic polymers. From the results of F-F-IR spectroscopy and quantum chemical calculations, it was determined that the high cooperativity of the syndiotactic polymers resulted from local formation of an ordered structure in a dehydrated state.